We used WKY rats.(1)After the treadmill exercise for 4 weeks (EX), the left coronary artery was ligated for 30min and then reperfused (ischemia reperfusion, IR). Four weeks later, left ventricular end-diastolic diameter (LVDd) in the EX group was significantly shorter than that in the no-exercise (no-EX) group, and left ventricular ejection fraction (LVEF) in the EX group was significantly more than that in the no-EX group.(2)After the IR, EX was performed. The values of LVDd and urine volume in the EX group were significantly lower than those in the no-EX group, and the values of LVEF and heart rate were significantly higher than those in the no-EX group.(3)The treatments with EX and the administration of valsartan for 4 weeks were performed before and after the IR. The values of blood pressure, urine volume, body weight in the treated-group were significantly lower than those in the non-treated-group, and heart weight was significantly lighter than that in the non-treated-group. The value of TNF-α m-RNA of non-ischemic left ventricular myocardium in the treated-group was significantly higher than that in the non-treated-group. The survival rate in the treated-group was significantly higher than that in the non-treated-group.(4)The EX was performed before and after the ligation of left coronary artery. The survival rate in the EX group was significantly higher than that in the no-EX group. The value of the oxygen intake during exercise in the EX group at 1 week after the ligation was significantly higher than that in the no-EX group.These results suggest that the EX before and/or after the cardiac ischemia improves the cardiac and cardiorespiratory functions, and the survival rate. These results also suggest that the TNF-α may play a important role in these cardioprotective effects of EX and valsartan.